<style>
    .mod_service_online{ width:85px; height:102px; position:fixed; _position:absolute; right:10px; bottom:200px; z-index:111;
        _position: absolute;
        _bottom: auto;
        clear: both;
        _top:expression(eval(document.compatMode &&
        document.compatMode=='CSS1Compat') ?
        documentElement.scrollTop
        +(documentElement.clientHeight-this.clientHeight-200) + 1
        : document.body.scrollTop
        +(document.body.clientHeight-this.clientHeight-200) - 1); }
    .mod_service_online img {
            border: 1px solid #6fb7bf;
            margin-top: -1px;}
</style>
<div class="mod_service_online">
    <a id="top_btn" href="javascript:void(0);"><img onmouseover="this.src='{{url('static','images')}}/to_top_cn.png';" onmouseout="this.src='{{url('static','images')}}/to_top.png';" src="{{url('static','images')}}/to_top.png" alt="回到顶部"></a>
</div>
<script>
    $(".mod_service_online #top_btn").click(function(){
        $("html,body").animate({scrollTop: 0},"slow");
    });
</script>

